| Jesus M. Salvo Jr. 2005-10-27, 8:21 am |
| Jesus M. Salvo Jr. wrote:
> Jesus M. Salvo Jr. wrote:
>
>
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>
>
> After further investigation, the application insert rows into the table
> with an initial value for the " notification_sent_to
_external" as
> '1753-01-01 00:00:00'.
>
> Once the rows are processed, they are then updated to the current datetime
> ( getdate() ).
>
> So it seems that these update on the column is causing the leaf pages on
> indexes to be moved to a different intermediate page(s) .. but can it
> fully explain the slowness that I am seeing ??
I am trying to find out what does ASE do in the event of updating a column
that is part of an index. The URL below shows what happens with an insert
and delete ... but does not mention what happens to a non-clustered index
in an update on a DOL table:
http://manuals.sybase.com:80/online...1362;pt=21362#X
Also, I have changed the application so that the initial value is now
'1753-01-01 00:00:01' instead of '1753-01-01 00:00:00'.
Now the first few minutes, "set statistics io" show very few logical pages
read. However, as time goes by, the number of logical pages read increases
in small increments.
Table: message_notification
_history scan count 1, logical reads: (regular=91
apf=0 total=91), physical reads: (regular=0 apf=0 total=0), apf IOs used=0
Total writes for this command: 0
Table: message_notification
_history scan count 1, logical reads:
(regular=103 apf=0 total=103), physical reads: (regular=0 apf=0 total=0),
apf IOs used=0
Total writes for this command: 0
Table: message_notification
_history scan count 1, logical reads:
(regular=107 apf=0 total=107), physical reads: (regular=0 apf=0 total=0),
apf IOs used=0
Total writes for this command: 0
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